Portable self-contained X-ray apparatus



Feb. 1, 1938.

H. L, J. MARSHALL 2,106,873 Y PORTABLE SELF CONTAINED X-RAY APPARATUS II Fild Sept. 16, 1955 3 SheetS- -Sheet 1 me .mwkmk v INVENTOR. Han-Li"than L.J.Mar*s=ha11 wwa Feb. 1, 1938. H. L. .J. MARSHALL PORTABLE SELFCONTAINED X-RAY APPARATUS I 5 Sheets-Sheet 2 Filed Sept. 16, 1935 Feb.1, 1938. H, L. J. MARSHALL 2,106,873

PORTABLE SELF CONTAINED X-RAY APPARATUS INVENTOR,

Hamill'nn L.. I.I"Iar* sh all ATTORNEY Patented Feb. 1, 1938 UNITEDSTATES PORTABLE SELF-CONTAIN ED X-RAY APPARATUS Hamilton L. J. Marshall,Troy, Ala., assignor to Osteograf 00., Inc., Troy, Ala., a corporationof Alabama Application September 16, 1935, Serial No. 40,843

6 Claims.

The present invention relates to X-ray apparatus and the primary objectof the invention is to provide a portable, self-contained X-ray ma chineor apparatus which is entirely independent of any external source ofpower.

A further and important object of the invention is to provide a portableX-ray machine which may be constructed at comparatively low cost and onewherein extreme economy of operation will be had since no batteries arerequired for its operation.

A further object resides in the provision of apparatus of this characterembodying a spring motor driven electrostatic machine or generator l ofimproved construction, with timing means for automatically controllingthe motor to permit the apparatus to run for various periods of time inaccordance with the desired time exposure.

A further object is to provide apparatus of this character employing ahot cathode X-ray tube (such as the Coolidge tube), with anelectrostatic generatcr and a low tension generator driven by a springmotor for operating the tube.

Other objects and advantages of the invention will be apparent from thefollowing detailed description, taken in connection with theaccompanying drawings forming a part of this specification and in whichdrawings:

Figure 1 is a perspective View of the X-ray ap paratus shown in use.

Figure 2 is a vertical longitudinal section thru the apparatus.

Figure 3 is an enlarged detail side View of the spring motor andassociated mechanism shown in an operating position.

Figure 4 is a View similar to Figure 3 but showing the brake mechanismhaving been released for stopping operation of the apparatus.

Figure 5 is a fragmentary section on the line 5-5 of Figure 3.

Figure 6 is a fragmentary perspective view showing the starter means forreleasing the brake mechanism and setting the apparatus for operation.

Figure 7 is a wiring diagram showing the position of switches, etc.,during operation of the apparatus such as shown in Figure 3.

Figure 8 is a wiring diagram showing the position of switches, etc.,when the brake mechanism has been released as shown in Figure 4.

Referring to the drawings in detail and wherein like referencecharacters designate corresponding parts thruout the several views, theapparatus comprises an elongated closed case A of a suitable insulatingmaterial and preferably semi-circular shape providing an arched upperwall 5, a fiat bottom wall 6 and parallel semicircular side walls 'I. Asuitable carrying handle 8 may be attached to the case for easilytransporting the apparatus. Provided at each lower corner of the case isan adjustable supporting leg 9 whereby the case may be verticallyadjusted with respect to its supporting surface.

Arranged within the case A is a suitable spring motor B providingdriving means for the improved electrostatic generator C and a lowtension generator D. The letter E designates a hot cathode vacuum X-raytube operating on the principle of the Coolidge tube but possessingimproved features as. will be subsequently described.

Referring particularly to Figures 3 and 4, the spring motor B may be ofany approved type and in the example shown is substantially of the typesuch as shown in U. S. Patent #lAZlAM, granted July 4, 1922. The motor Bis mounted in one end portion of the case A and embodies a frame ithaving mounted therein a spring barrel H revolving about a verticalaxis. Operatively connected with the upper portion of the spring barrelII is a gear I2 connected by suitable gearing with a winding shaft I3which extends toward one end of the case for attachment of a windingcrank 14 adapted for winding the motor. Operatively associated with thelower end of the spring barrel H is a gear 15 meshing with a pinion Iton a shaft ll. Mounted on the shaft I1 is a large gear I 8 meshing witha pinion 19 on the lower end of a vertical drive shaft 20 which extendsupwardly above the motor frame lfi. Secured on the drive shaft 20 is aworm gear 2! meshing with a Worm 22 on a horizontally disposed governorshaft 23 having a fly ball governor 24 mounted thereon embodying a flatdisc 25 for cooperating with a speed regulator 26 which is preferablyadjustable for regulating the speed of the drive shaft 20.

Referring now to the electrostatic machine or generator 0, the same isadapted to generate static electricity by electrostatic induction andembodies a pair of substantially identical static units 30 and 3|arranged vertically in the case A midway between the ends thereof. Theunits 30 and 3! are of the endless belt type and each embodies an uppersupporting roller 32 and a lower drive roller 33, each formed of asuitable insulating material such as hard rubber, mica, etc. Trainedover each pair of rollers 32 and 33 is an endless, non-conducting belt34 which is preferably formed of silk. Arranged between the parallelvertical runs of each belt 34 is a glass plate 35 having its faces inslightly spaced relation to the runs of the belt and with the upper andlower edges of the plate terminating in spaced relation to the rollers32 and 33. The units 30 and 3| are suitably mounted in close proximityto one another and in parallel spaced apart relation with the spacingbetween the units being approximately two inches.

Secured to one end of each of the lower drive rollers 33 is a bevel gear36, and these gears each mesh with bevel gears 31 mounted upon a shaft38 journaled longitudinally in the case A with one end extending abovethe spring motor B. As will be observed in Figure 2, the bevel gears 31are oppositely arranged on the shaft 38 so that the endless belts 34will be caused to run in opposite directions to one another, thuscausing one of the static units to receive a negative charge and theother unit a positive charge.

Associated with the upper ends of the units 30 and 3! are collectingcombs 40 and 4|, to which are respectively connected high tensionconductors 42 and 43 for delivering high tension current to the tube E.Provided in the conductor 42 is a spark gap 44 for intensifying thecurrent delivered to the tube. Connected in series across the conductors42 and 43 is a bank of condensers or accumulators 45 which in theexample shown are in the form of Leyden jars, each provided with theusual outer coatings 46 and with rods 41 which connect the innercoatings of the jars with the conductors 42 and 43. These outer andinner coatings may be a thin, highly conductive metal foil such astinfoil, aluminum, copper, silver, etc. The outer coatings 4B areconnected by a conductor 48 whereby the accumulators 45 are connected inparallel with the tube E.

Arranged between the adjacent runs of the belts 34 is an equalizer 49which may be in the form of a metallic arm spaced slightly from thebelts and serving to ground any overflow of current thru the conductor59 which may be connected to one of the bearings for the shaft 38whereby the equalizer is grounded upon the metal framework of theapparatus.

The low tension generator D provides current for heating the cathode ofthe X-ray tube E and this generator is preferably mounted directly uponthe upper side of the spring motor frame ID with the vertical driveshaft 20 forming the generator shaft. The shaft 20 projects above thegenerator and has mounted thereon a bevel gear which meshes with a bevelgear 52 on the shaft 38. Thus the spring motor B serves to operate boththe electrostatic generator C and also the low tension generator D.Connected with the generator D are the low tension conductors 53 and 54which connect with the heater element of the tube E.

The hot cathode X-ray tube E may be of the radiator type Coolidge tubeand embodies the usual tube or envelope 55 in which is sealed an anode53 provided with the usual target 51, and a cathode adapted to be heatedand to which the low tension conductors 53 and 54 are connected. Withthe usual type of hot cathode X-ray tube, the cathode usually consistsof a resistance wire filament. These filaments after repeated heatingwill warp and otherwise deviate from the proper alignment thus causing achange of the focal spot. To overcome this difiiculty, I substitute forthe usual resistance wire filament, a solid block of carborundum 58 sothat all possibilities of warping are eliminated and a true focal spotcan be maintained indefinitely. In operation, the carborundum cathode 58is heated to a degree suitable for the emission of electrons. Thecarborundum cathode is heated to a temperature of 1500 degreescentigrade, this being the temperature at which carborundum beginsemitting electrons in vacuum, and being the point at which this materialreaches incandescence. This heater block also eliminates burning out ofthe heater thru overloads or becoming otherwise injured.

The tube E is mounted upon the lower wall 6 of the case A midway betweenthe ends of the case, directly above a. tube cone 59 which projectsbelow the case as clearly shown in Figure 2. This tube cone 59- isformed of thin. aluminum and aside from serving to filter some of theundesirable gamma rays, also serves to indicate the center of the focalspot of the tube so as to enable the operator to correctly approximatehis work.

Timing means is provided to permit the apparatus to run for apredetermined length of time necessary to make the proper penetration ofthe part to be X-rayed so as to make the proper exposure, and comprisesa timing control device 60 which operates to control a manually releasedstop means 6! for the spring motor B.

The timing device 58 comprises a control shaft 63 journaled in thespring motor frame It beside the shaft I"! with one end of the controlshaft extending thru a graduated exposure dial 64 mounted upon one ofthe casing side walls 7 and provided with a pointer 65. An anatomicalchart 66 giving the calibration of the timer in relation to differentanatomical regions of 1e body is printed or otherwise provided on thecase adjacent the dial 54. Frictionally carried by the shaft 63 is aworm wheel 68 which meshes with a worm 61 on the shaft I? wherebyrotation will be imparted to the control shaft during running of thespring motor. Fixed upon the shaft 63 is a timer cam or eccentric 68which co-acts with a spring switch lever 69 serving to control a pair ofswitches Ill and it in accordance with the relation of the cam to theswitch lever. Each of the switches and "H in the example shown, embodiesa fixed contact and a movable contact normally spring urged out ofengagement with its fixed contact. By referring to Figures '7 and 8 itwill be seen that the switch 19 is connected in the low tensionconductor 54 and controls the filament cathode circuit of the tube E.

The stop means 5! for stopping the spring motor after the apparatus hasrun for the set period of time, embodies a solenoid 12 suitably mountedupon the motor frame it and having its armature 13 connected with aspring lever 14 provided with a notch l5. This spring lever '14 has itsarmature connected end normally spring urged away from the solenoid. Thesolenoid is energized by the low tension generator D thru the conductorsand H. The switch H is connected in the conductor 16 so that this switchserves to control the solenoid circuit.

The spring motor B is normally held against running by a brakearrangement embodying a brake lever 89 pivoted intermediate its endsupon the spring motor frame [6 and provided at one end with a brake shoe8| normally held in braking engagement against the peripheral edge ofthe speed regulator disc by a suitable spring 82. The end of this brakelever 35 is arranged to be engaged in the notch 15 of the spring lever14 when the apparatus is set for operation as shown in Figure 3. A meansis provided for releasing the brake lever from a braking position andembodies a starting shaft 83 provided with a pointer handle 84 forrotating the shaft to an on position when starting the apparatus. Theinner end of this shaft 83 carries a lever 85 arranged to engage thebrake lever 80 and swing the lever so as to be engaged in the notch 75thus releasing the brake shoe 8| from engagement with the disc 25.

In Figure l, the letter F designates a film holder or cassette and whilevarious types of film holders may be used, it is preferred to usecassettes such as described in U. S. Patent 1,879,498, permittingdeveloping of the film in the field.

As to the mode of operation, the spring motor B is first wound by meansof the crank I4 and with the pointer handle 84 in the off positionallowing the brake shoe 81 to engage and hold the disc 25 againstrotation as in Figure 4. The operator then determines, by consulting theanatomical chart 66, the number on the dial 64 suitable for an exposureof the part to be X- rayed and sets the pointer 65 to the proper numberon the dial 64. This setting of the pointer 64 rotates the control shaft63 and the cam 68 which causes the switch lever 69 to open the switch Hand close the switch 10 thus opening the solenoid circuit and closingthe cathode circuit as in Figures 3 and '7. The pointer handle 84 is nowswung to an on position causing the lever 84 to swing the brake leverBil so as to be engaged and held in the notch 15 of the spring lever 14thus releasing the brake shoe 8! and allowing operation of the springmotor B. Running of the spring motor B operates the electrostaticgenerator C and the low tension generator D thus energizing the X-raytube E. This running of the spring motor imparts rotation to the controlshaft 63 thru the shaft l1, worm 61 and worm gear 66 whereby, when thepointer 65 has returned to zero position, the cam 68 allows the switchlever 69 to lower thus opening the switch 10 in the cathode circuit andclosing the switch H in the solenoid circuit as in Figures 4 and 8.Closing of the switch H energizes the solenoid 12 which actuates thearmature l3 and exerts a pull on the spring lever 14 and allows thebrake lever to be disengaged from the notch 15. The spring 82 thenexerts a pull on the brake lever 80 causing the brake shoe 8| to engagethe disc 25 and stop operation of the apparatus. The brake lever 8|]when released, strikes a bell thus giving a stop signal.

While the machine has been shown and described as being primarilydesigned for use as a portable, self-contained X-ray apparatus, it willreadily be apparent that the apparatus is not limited for use as aportable device, and that other forms of driving means may besubstituted for the specific spring motor driving means as shown.

Changes in details may be made to the form of invention herein shown anddescribed, without departing from the spirit of the invention or thescope of the following claims.

I claim:

1. In apparatus of the class described, an X-ray tube, a high voltagegenerator and a low voltage generator for energizing the tube, a springmotor, drive means between the spring motor and the generators, stopmeans normally holding the spring motor against operation, startingmeans for releasing the stop means, electrically released holding meansfor retaining the stop means released, and timing control means for theholding means for controlling the duration of spring motor operation.

2. In a portable, self contained X-ray apparatus, a casing havingsupporting means, an electrostatic generator in the case, a low tensiongenerator in the case, an X-ray tube in the case to be energized by saidgenerators, a single driving means in the case for operating saidgenerators, manually releasable stop means normally holding the drivingmeans against operation, electrically releasable holding means forretaining the stop means released, and adjustable timing control meansfor automatically releasing the holding means to permit stopping of thedriving means by said stop means.

3. In apparatus of the class described, a case, a hot cathode X-ray tubein the case, an electrostatic generator in the case, a high tensioncircuit between the generator and the tube, a low tension generator inthe case, a low tension circuit between the low tension generator andthe tube, a spring motor in the case for operating said generators, stopmeans for the spring motor and manually releasable to permit operationof the motor, electrically released holding means for the stop meanswhen released, and variable timing control means operable by the motorfor opening the low tension circuit and causing release of the holdingmeans for stopping operation of the spring motor.

4. In a portable X-ray apparatus of the class described, a hot cathodeX-ray tube, an electrostatic generator for the tube, a low tensiongenerator for the tube, a cathode circuit between the tube and lowtension generator, spring motor drive means for the generators, asolenoid, a solenoid circuit energized by the low tension generator, abrake member normally holding the motor against operation, a holdinglever engageable with the brake member for holding the brake memberreleased and releasable therefrom upon energizing the solenoid, and timecontrolled circuit controlling means for the solenoid circuit.

5. In X-ray apparatus of the class described, a hot cathode X-ray tube,an electrostatic generator, a high tension circuit between the generatorand tube, a low tension generator, a low tension circuit between the lowtension generator and the cathode of the tube, a spring motor foroperating both of said generators, a brake member normally holding thespring motor against operation, starting means for releasing the brakemember, electrically released holding means for retaining the brakemember released and adapted to be energized by the low tensiongenerator, and circuit controlling timing means operable by the springmotor for opening the low tension circuit and energizing the holdingmeans for releasing the brake member and stopping operation of theapparatus.

6. In X-ray apparatus of the class described, a hot cathode X-ray tube,a high tension generator and a low tension generator for energizing thetube, a low tension circuit, spring motor drive means for the generatorsand embodying governor means including a brake disc, a releasable brakelever having a brake shoe spring urged against the brake disc fornormally holding the spring motor against operating, starting means forreleasing the brake lever, solenoid controlled holding means releasablyengageable with the brake lever for holding the brake shoe released, andcircuit controlling means for the low tension circuit and the solenoidcontrolled holding means, and operable by the spring motor forcontrolling running time for the apparatus.

HAMILTON L. J. MARSHALL.

